Method of manufacturing electron multiplier body, photomultiplier tube, and photomultiplier

ABSTRACT

A method of manufacturing an electron multiplier body, the method includes a step of preparing a first plate-like member having a surface and a back surface and a pair of second plate-like members, a step of forming, in the first plate-like member, a hole portion reaching from the front surface to the back surface, a step of constituting a laminated body by laminating the first and second plate-like members on each other so that the first plate-like member is interposed between the pair of second plate-like members to form a channel defined by the hole portion in the laminated body, a step of integrating the laminated body, a step of constituting a main body portion by cutting the integrated laminated body so that the channel is open, and a step of forming a resistive layer and a secondary electron multiplication layer on an inner surface of the channel.

TECHNICAL FIELD

An aspect of the present invention relates to a method of manufacturingan electron multiplier body, a photomultiplier tube, and aphotomultiplier.

BACKGROUND

An electron multiplier body including a rectangular parallelepipeddynode element in which a wavy passage is provided is described inPatent Document 1 (U.S. Pat. No. 3,244,922). In this electron multiplierbody, two blocks having wavy groove portions formed therein are combinedto form a passage and a dynode element.

SUMMARY

In the electron multiplier body described in Patent Document 1, therespective wavy groove portions are formed in the two blocks andcombined to form the passage (a channel), as described above. However,in such a method, it is difficult to improve processability of thechannel.

An aspect of the present invention has been made in view of suchcircumstances and an object of an aspect of the present invention is toprovide a method of manufacturing an electron multiplier body, aphotomultiplier tube, and a photomultiplier capable of improvingprocessability of a channel.

A method of manufacturing an electron multiplier body according to anaspect of the present invention is a method of manufacturing an electronmultiplier body including a main body portion extending in a firstdirection, and a channel opened at one end surface and the other endsurface of the main body portion in the first direction and emitssecondary electrons according to incident electrons, the methodincluding: a preparing step of preparing a first plate-like memberhaving a front surface and a back surface opposite to the front surface,and a pair of second plate-like members; a hole forming step of forming,in the first plate-like member, a hole portion reaching from the frontsurface to the back surface and extending along the front surface andthe back surface; a laminating step of constituting a laminated body bylaminating the first and second plate-like members on each other so thatthe first plate-like member is interposed between the pair of secondplate-like members to form the channel defined by the hole portion inthe laminated body; an integrating step of integrating the laminatedbody; a cutting step of constituting the main body portion by cuttingthe integrated laminated body; and a layer forming step of forming aresistive layer and a secondary electron multiplication layer on aninner surface of the channel, wherein in the cutting step, the laminatedbody is cut so that the channel is open at the one end surface and theother end surface.

In the method of manufacturing the electron multiplier body, the holeportion reaching from the front surface to the back surface andextending along the front surface and the back surface is formed in thefirst plate-like member. The first and second plate-like members arelaminated on each other so that the first plate-like member isinterposed between the pair of second plate-like members to constitutethe laminated body and form the channel defined by the hole portion. Thelaminated body is integrated and cut to constitute the main bodyportion. Further, the resistive layer and the secondary electronmultiplication layer are formed on the inner surface of the channel.According to this method, it is possible to improve the processabilityof the channel since it is relatively easy to form the hole portion inthe plate-like member. Further, for the same reason, it is possible toreduce manufacturing cost.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention, in the layer forming step, theresistive layer and the secondary electron multiplication layer mayformed using an atomic layer deposition (ALD) method. In this case, itis possible to easily form the resistive layer and the secondaryelectron multiplication layer on an inner surface of the channel.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention, the first and second plate-likemembers may be formed of a conductor, and the method may further includean insulating film forming step of forming an insulating film on asurface of the main body portion and the inner surface of the channelbefore the layer forming step. In this case, since a conductor can beused as the first and second plate-like members, it is possible tomanufacture the electron multiplier body using a variety of materials.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention, the hole portion may be formed toreach one end or the other end of the first plate-like member in thefirst direction in the hole forming step. In this case, before thecutting step, the hole portion reaches any one of the one and the otherend of the first plate-like member. Therefore, in the cutting step, thechannel can be open at the one end surface and the other end surface ofthe main body portion by simply cutting only the other of the one endand the other end of the first plate-like member. Further, before thecutting step, the hole portion does not reach the other of the one endand the other end of the first plate-like member. Therefore, it ispossible to prevent the first plate-like member from being divided intotwo portions. Accordingly, it is possible to improve workability.Further, it is possible to make the width of the channel accurately andconveniently.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention, in the hole forming step, the holeportion may be formed not to reach end portions of the first plate-likemember. In this case, before the cutting step, the hole portion does notreach the end portions of the first plate-like member. Therefore, it ispossible to more reliably prevent the first plate-like member from beingdivided into two portions. Accordingly, it is possible to improve theworkability. Further, it is possible to make the width of the channelaccurately and conveniently.

In the electron multiplier body according to an aspect of the presentinvention, the thickness of the first and second plate-like members maybe 5 mm or less. In this case, since the first and second plate-likemembers are relatively thin, formation of the hole portion becomeseasier. Therefore, it is possible to further improve the processabilityof the channel.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention; a plurality of the first plate-likemembers may be prepared, and a third plate-like member may be furtherprepared in the preparing step, and in the laminating step, the first,second, and third plate-like members may be laminated on each other sothat the third plate-like member is interposed between the firstplate-like members and the first and third plate-like members areinterposed between the pair of second plate-like members to constitutethe laminated body. In this case, since the first plate-like member isinterposed between the third plate-like member and each of the pair ofsecond plate-like members, a plurality of channels are constituted in alaminating direction thereof. Therefore, it is possible to easilymanufacture the electron multiplier body with multiple channels.

In the method of manufacturing an electron multiplier body according toan aspect of the present invention, a plurality of the hole portions maybe formed in the first plate-like member in the hole forming step. Inthis case, a plurality of channels are formed in a direction along thefront and back surfaces of the first plate-like member. Therefore, it ispossible to easily manufacture the electron multiplier body withmultiple channels.

A photomultiplier tube according to an aspect of the present inventionis a photomultiplier tube including the electron multiplier bodymanufactured using the method of manufacturing an electron multiplierbody; a tube body accommodating the electron multiplier body; aphotocathode provided in the tube body to face an opening of the channelin the one end surface and configured to supply photoelectrons to thechannel; and an anode arranged in the tube body to face an opening ofthe channel in the other end surface and configured to receive secondaryelectrons emitted from the channel according to the photoelectronsincident on the channel.

This photomultiplier tube includes an electron multiplier bodymanufactured using the above-mentioned method of manufacturing anelectron multiplier body. Therefore, it is possible to achieve theoperations and effects.

A photomultiplier according to an aspect of the present invention is aphotomultiplier including the electron multiplier body manufacturedusing the method of manufacturing an electron multiplier body; aphotocathode provided to close an opening of the channel at the one endsurface and configured to supply photoelectrons to the channel; and ananode provided to close an opening of the channel in the other endsurface and configured to receive secondary electrons emitted from thechannel according to the photoelectrons incident on the channel.

This photomultiplier includes an electron multiplier body manufacturedusing the above-mentioned method of manufacturing an electron multiplierbody. Therefore, it is possible to achieve the operations and effects.

According to an aspect of the present invention, it is possible toimprove the processability of the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a photomultiplier tube according toan embodiment.

FIG. 2 is a perspective view of an electron multiplier body according tothe embodiment.

FIGS. 3A and 3B are views illustrating a step of a method ofmanufacturing an electron multiplier body according to the embodiment.

FIG. 4 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the embodiment.

FIG. 5 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the embodiment.

FIG. 6 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the embodiment.

FIG. 7 is a view illustrating a step of the method of manufacturing theelectron multiplier body according to the embodiment.

FIG. 8 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the embodiment.

FIGS. 9A and 9B are views illustrating an electron multiplier bodymanufactured using a method of manufacturing an electron multiplier bodyaccording to a first modification example.

FIGS. 10A and 10B are views illustrating an electron multiplier bodymanufactured using a method of manufacturing an electron multiplier bodyaccording to a second modification example.

FIG. 11 is a view illustrating an electron multiplier body manufacturedusing a method of manufacturing an electron multiplier body according toa third modification example.

FIGS. 12A to 12C are views illustrating a step of the method ofmanufacturing an electron multiplier body according to the thirdmodification example.

FIG. 13 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the third modification example.

FIG. 14 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the third modification example.

FIG. 15 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the third modification example.

FIG. 16 is a view illustrating a step of the method of manufacturing anelectron multiplier body according to the third modification example.

FIG. 17 is a cross-sectional view of a photomultiplier to which theelectron multiplier body illustrated in FIG. 2 is applied.

DETAILED DESCRIPTION

Hereinafter, an embodiment of an aspect of the present invention will bedescribed in detail with reference to the drawings. The same orcorresponding portions in the respective drawings are denoted with thesame reference signs, and repeated description is omitted.

FIG. 1 is a cross-sectional view of a photomultiplier according to theembodiment, and FIG. 2 is a perspective view of an electron multiplierbody according to the embodiment. As illustrated in FIGS. 1 and 2, aphotomultiplier tube 1 includes an electron multiplier body 2, a tubebody 3, a photocathode 4, and an anode 5. The electron multiplier body 2multiplies electrons by emitting secondary electrons according to theincidence of electrons. The electron multiplier body 2 includes a mainbody portion 6, and a channel 8.

The main body portion 6 extends in a first direction D1. Further, themain body portion 6 is formed in a rectangular parallelepiped shape. Themain body portion 6 includes one end surface 6 a and the other endsurface 6 b in the first direction D1. At least a surface of the mainbody portion 6 is formed of an insulator. Here, for example, the mainbody portion 6 is formed of a ceramic which is an insulator.

The channel 8 emits secondary electrons according to incident electrons.The channel 8 includes an electron incidence portion 8 a and amultiplier portion 8 b. The electron incidence portion 8 a is an inletportion for causing electrons to be incident from the outside of themain body portion 6 to the inside of the main body portion 6. Theelectron incidence portion 8 a is provided in the main body portion 6 tobe open at the one end surface 6 a of the main body portion 6 in thefirst direction D1. An opening of the electron incidence portion 8 a atthe one end surface 6 a exhibits a rectangular shape when viewed fromthe first direction D1. Further, the electron incidence portion 8 a isgradually narrowed in a second direction D2 to be described later alongthe first direction D1. That is, the electron incidence portion 8 aexhibits a tapered shape reduced along the first direction D1.

The multiplier portion 8 b emits the secondary electrons according tothe electrons incident from the electron incidence portion 8 a. Themultiplier portion 8 b is open at the other end surface 6 b of the mainbody portion 6 in the first direction D1. An opening of the multiplierportion 8 b at the other end surface 6 b faces the anode 5. Themultiplier portion 8 b is provided in the main body portion 6 to reachthe electron incidence portion 8 a. Therefore, the channel 8, as awhole, is open at the one end surface 6 a and the other end surface 6 bof the main body portion 6.

The multiplier portion 8 b includes a first inner surface 9 and a secondinner surface 10 extending over the entire multiplier portion 8 b in thefirst direction D1 and facing each other. The first inner surface 9 andthe second inner surface 10 are spaced in the second direction D2intersecting the first direction D1. The second direction D2 is adirection from the first inner surface 9 to the second inner surface 10.Here, the second direction D2 is a direction perpendicular to the firstdirection D1.

The first inner surface 9 includes a first convex bent portion 9 a and asecond concave bent portion 9 b which are arranged alternately along thefirst direction D1. Further, the first inner surface 9 includes aplurality of first inclined surfaces 9 c defining each of the first bentportion 9 a and the second bent portion 9 b. The first inclined surface9 c has a planar shape. In this embodiment, the first bent portion 9 aand the second bent portion 9 b are bent in an angular shape.

The second inner surface 10 includes a third convex bent portion 10 aand a fourth concave bent portion 10 b which are arranged alternatelyalong the first direction D1. Further, the second inner surface 10includes a plurality of second inclined surfaces 10 c defining each ofthe third bent portion 10 a and the fourth bent portion 10 b. The secondinclined surface 10 c has a planar shape. In this embodiment, the thirdbent portion 10 a and the fourth bent portion 10 b are bent in anangular shape.

That is, the first inner surface 9 and the second inner surface 10 areformed to be repeatedly bent in a zigzag shape (for example, a wavyshape) along the first direction D1. Here, in the first inner surface 9and the second inner surface 10, the first bent portion 9 a and thefourth bent portion 10 b face each other, the second bent portion 9 band the third bent portion 10 a face each other, and the first inclinedsurface 9 c and the second inclined surfaces 10 c face each other in thesecond direction D2.

A resistive layer and a secondary electron multiplication layer areprovided to be laminated on each other on the inner surface of theelectron incidence portion 8 a and the inner surface (at least the firstinner surface 9 and the second inner surface 10) of the multiplierportion 8 b. The surface of the electron incidence portion 8 a and thesurface of the multiplier portion 8 b form the secondary electronmultiplication layer. For example, a mixed film of aluminum oxide(Al₂O₃) and zinc oxide (ZnO), a mixed film of Al₂O₃ and titanium dioxide(TiO₂), or the like can be used as a material of the resistive layer.For example, Al₂O₃, magnesium oxide (MgO), or the like can be used asmaterial of the secondary electron multiplication layer.

Further, metal layers 11 and 12 containing a nickel-based metal areprovided on the one end surface 6 a and the other end surface 6 b of themain body portion 6 using a method such as vapor deposition,respectively. A potential difference is given to the main body portion 6so that the metal layer 12 provided on the other end surface 6 b has ahigher potential than that of the metal layer 11 provided on the one endsurface 6 a. By the potential difference being given in this way, apotential difference in the first direction D1 is generated in thechannel 8.

The main body portion 6 is configured by laminating first and secondplate-like members 21 and 22 on each other so that a plurality of (here,four) first plate-like members 21 are interposed between a pair ofsecond plate-like members 22, as will be described later. Accordingly,hole portions 24 formed in each of the first plate-like members 21 areconnected to each other, and both ends thereof in a laminating directionare closed by the second plate-like members so that the channel 8 isconfigured.

The tube body 3 accommodates the electron multiplier body 2. Asillustrated in FIG. 1, the tube body 3 extends in the first directionD1. In the first direction D1, one end 3 a of the tube body 3 is openand the other end 3 b is sealed. Here, the one end surface 6 a of themain body portion 6 of the electron multiplier body 2 is located at theone end 3 a of the tube body 3, and the other end surface 6 b of themain body portion 6 of the electron multiplier body 2 is located at theother end 3 b of the tube body 3.

The photocathode 4 generates photoelectrons according to the incidenceof light. The photocathode 4 has a flat plate shape. The photocathode 4is provided to close the opening at the one end 3 a of the tube body 3.The photocathode 4 faces the opening of the electron incidence portion 8a at the one end surface 6 a of the main body portion 6 of the electronmultiplier body 2. Accordingly, the photoelectrons generated in thephotocathode 4 are supplied to the electron incidence portion 8 a. In astate in which the opening at the one end 3 a of the tube body 3 isclosed by the photocathode 4, the inside of the tube body 3 is reducedin pressure.

The anode 5 receives the secondary electrons which are emitted from thechannel 8 according to the photoelectrons incident on the channel 8. Theanode 5 has a flat plate shape. The anode 5 is arranged within the tubebody 3 to face the opening of the multiplier portion 8 b at the otherend surface 6 b of the main body portion 6. The anode 5 is arranged tobe spaced from the other end surface 6 b of the main body portion 6 andthe other end 3 b of the tube body 3. A detector (not illustrated) thatdetects pulses of an electrical signal corresponding to the secondaryelectrons received by the anode 5 is connected to the anode 5.

Subsequently, a method of manufacturing the electron multiplier body 2as described above will be described. In this manufacturing method, asillustrated in FIGS. 3A and 3B, a plurality of (here four) firstplate-like members 21 including a surface 21 a and a back surface 21 bopposite to the surface 21 a, and a pair of second plate-like members 22are first prepared (a preparing step). Here, hole portions 24, whichwill be described later, are not formed in the first plate-like members21. The first and second plate-like members 21 and 22 exhibit arectangular shape. Further, a thickness of each of the first and secondplate-like members 21 and 22 is 5 mm or less. The first and secondplate-like members 21 and 22 are formed of a ceramic which is aninsulator. Here, since the first and second plate-like members 21 and 22are formed of the ceramic, the first and second plate-like members 21and 22 can be formed to be relatively thin by performing a laminatingstep through roll compaction.

In a subsequent step, a plurality of (here six) hole portions 24 areformed in the first plate-like member 21 (a hole forming step). The holeportion 24 can be formed by, for example, laser machining, punchingusing a mold, or the like. The hole portions 24 reach from the surface21 a to the back surface 21 b, and extend along the surface 21 a and theback surface 21 b. The hole portions 24 are arranged two-dimensionallyin the first direction D1 and the second direction D2.

The hole portions 24 extend in the first direction D1. Specifically, thehole portion 24 includes a triangular portion 24 a formed in atriangular shape spread in a direction opposite to the first directionD1, and an extending portion 24 b extending in the first direction D1from the triangular portion 24 a. However, the hole portion 24 is formednot to reach end portions of the first plate-like member 21(particularly, one end 25 and the other end 26 in the first directionD1).

In a subsequent step, as illustrated in FIGS. 4 and 5, the first andsecond plate-like members 21 and 22 are laminated on each other so thatthe first plate-like members 21 are interposed between the pair ofsecond plate-like members 22 and a laminated body 27 is formed (alaminating step). Here, the four first plate-like members 21 areinterposed between the pair of second plate-like members 22. Bylaminating the first and second plate-like members 21 and 22 on eachother in this way, a plurality of channels 8 defined by the holeportions 24 are formed in the laminated body 27. Here, the triangularportions 24 a of the hole portions 24 constitute the electron incidenceportion 8 a, and the extending portions 24 b constitute the multiplierportion 8 b (see FIG. 7). By adjusting the number of first plate-likemembers 21 to be laminated, it is possible to adjust a width of thechannel 8 in the laminating direction of the plate-like members.

In a subsequent step, the laminated body 27 is integrated (anintegration step). Here, the first and second plate-like members 21 and22 formed of a ceramic are pressed and sintered to be integrated.

In a subsequent step, the integrated laminated body 27 is cut toconstitute the main body portion 6 (a cutting step), as illustrated inFIGS. 6 and 7. In this cutting step, the laminated body 27 is cult alongvirtual cutting lines L1, L2, and L3 set in the laminated body 27. Thecutting lines L1, L2, and L3 are set in a grid pattern so that channels8 two-dimensionally arranged in the first direction D1 and the seconddirection D2 are carved one by one. The cutting line L is set along thefirst direction D1. The cutting line L1 defines a width of the main bodyportion 6 which is along the second direction D2. Each of the cuttinglines L2 and L3 are set along the second direction D2. The cutting linesL2 and L3 define a length of the main body portion 6 which is along thefirst direction D1. The cutting line L2 is set so that the electronincidence portion 8 a is open at a cut surface when cutting is performedalong the cutting line L2. Further, the cutting line L3 is set so thatthe multiplier portion 8 b is open at a cut surface when cutting isperformed along the cutting line L3. By cutting the laminated body 27along the cutting lines L1, L2, and L3 as described above, a pluralityof main body portions 6 each including a single channel 8 areconstituted.

In a subsequent step, a resistive layer and a secondary electronmultiplication layer are formed on the inner surface of the channel 8formed in the main body portion 6 (a layer forming step). Here, theresistive layer and the secondary electron multiplication layer areformed using an atomic layer deposition method. Through the above steps,a plurality of electron multiplier bodies 2 as illustrated in FIG. 8 aremanufactured.

As described above, in the method of manufacturing the electronmultiplier body 2 according to the embodiment, the hole portion 24reaching from the surface 21 a to the back surface 21 b and extendingalong the surface 21 a and the back surface 21 b is formed in the firstplate-like members 21. The first plate-like members 21 and the pair ofsecond plate-like members 22 are laminated on each other so that thefirst plate-like members 21 are interposed between the pair of secondplate-like members 22 to constitute the laminated body 27 and form thechannel 8 defined by the hole portion 24. This laminated body 27 isintegrated and cut to constitute the main body portion 6. Further, theresistance layer and the secondary electron multiplication layer areformed on the inner surface of the channel 8. According to this method,it is possible to improve the processability of the channel 8 since itis relatively easy to form the hole portion 24 in the plate-like member.Further, for the same reason, it is possible to reduce manufacturingcost.

Further, in the method of manufacturing the electron multiplier body 2,the resistive layer and the secondary electron multiplication layer areformed using an atomic layer deposition method in the layer formingstep. Accordingly, it is possible to easily form the resistive layer andthe secondary electron multiplication layer on the inner surface of thechannel 8.

Further, in the method of manufacturing the electron multiplier body 2,the hole portion 24 is formed not to reach the end portions of the firstplate-like member 21 in the hole forming step. Accordingly, before thecutting step, the hole portion 24 does not reach the end portion of thefirst plate-like member 21. Therefore, it is possible to more reliablyprevent the first plate-like member 21 from being divided into twoportions. Accordingly, it is possible to improve workability. Further,it is possible to make the width of the channel 8 accurately andconveniently.

Further, in the electron multiplier body 2, a thickness of the first andsecond plate-like members 21 and 22 is 5 mm or less. Accordingly, sincethe first and second plate-like members 21 and 22 are relatively thin,the formation of the hole portion 24 becomes easier. Therefore, it ispossible to further improve the processability of the channel 8.

In the photomultiplier tube 1 according to the embodiment, since theelectron multiplier body 2 manufactured using the above-described methodof manufacturing the electron multiplier body 2 is included, it ispossible to suitably achieve the operations and effects.

First Modification Example

Next, a method of manufacturing an electron multiplier body according tothe first modification example will be described. As illustrated in FIG.9A, an electron multiplier body 31 according to the first modificationexample includes an electron incidence portion 8 a exhibiting a funnelshape. That is, an opening of the electron incidence portion 8 a at oneend surface 6 a of a main body portion 6 is wider at a central portionin a laminating direction of plate-like members and narrower at portionscloser to both end portions thereof.

As illustrated in FIG. 9B, in order to constitute the electron incidenceportion 8 a as described above, in the method of manufacturing theelectron multiplier body 31, hole portions 24 of which spread angles oftriangular portions 24 a are different from each other are formed ineach first plate-like member 21 in a hole forming step. In a laminatingstep, the plurality of first plate-like members 21 are laminated so thatthe electron incidence portion 8 a exhibits the funnel shape describedabove. By performing such a step, it is possible to easily form thechannel 8 having the shape as described above.

Second Modification Example

Next, a method of manufacturing an electron multiplier body according tothe second modification example will be described. As illustrated inFIGS. 10A and 10B, an electron multiplier body 32 according to thesecond modification example includes a channel 8 exhibiting athree-dimensionally bent shape (for example, a helical shape). In themethod of manufacturing the electron multiplier body 32, hole portions24 of which shapes of triangular portions 24 a and extending portions 24b are different from each other are formed in each plate-like member 21in a hole forming step. In a laminating step, the plurality of firstplate-like members 21 are laminated so that the channel 8 exhibits athree-dimensionally bent shape. By performing such steps, it is possibleto easily form the channel 8 having the shape as described above.

Third Modification Example

Next, a method of manufacturing an electron multiplier body 33 will bedescribed. As illustrated in FIG. 11, the electron multiplier body 33according to the third modification example includes a plurality ofchannels 8 arranged two-dimensionally along a laminating direction ofplate-like members and a second direction D2. That is, the electronmultiplier body 33 is an electron multiplier body 33 with multiplechannels. In the method of manufacturing the electron multiplier body33, a plurality of first plate-like members 21, a pair of secondplate-like members 22, and a third plate-like member 23 are firstprepared (a preparation step). A shape, a material, and the like of thethird plate-like member 23 may be the same as those of the first andsecond plate-like members 21 and 22.

In a subsequent step, as illustrated in FIGS. 12A to 12C, a plurality ofhole portions 24 are formed in the first plate-like members 21 (a holeforming step). Here, the hole portions 24 are arranged two-dimensionallyalong a first direction D1 and the second direction D2. In the exampleillustrated in FIGS. 12A to 12C, two hole portions 24 in the firstdirection D1 and two hole portions 24 in the second direction D2 areformed side by side.

In a subsequent step, the first, second, and third plate-like members21, 22, and 23 are laminated on each other so that the third plate-likemember 23 is interposed between the first plate-like members 21 and thefirst plate-like members 21 are interposed between the pair of secondplate-like members 22 to constitute the laminated body 27 (a laminatingstep), as illustrated in FIG. 13. That is, here, the second plate-likemember 22, two of the first plate-like members 21, the third plate-likemember 23, two of the first plate-like members 21, and the secondplate-like member 22 are laminated in this order. By laminating thefirst, second, and third plate-like members 21, 22, and 23 on each otherin this way, each channel 8 defined by the hole portions 24 are formedin the laminated body 27 in each of the first plate-like members 21 onboth surfaces of the third plate-like member 23 (see FIG. 16).

In a subsequent step, the laminated body 27 is integrated (anintegrating step), as illustrated in FIG. 14.

In a subsequent step, the integrated laminated body 27 is cut toconstitute the main body portion 6 (a cutting step), as illustrated inFIGS. 15 and 16. In the cutting step, the laminated body 27 is cut alongvirtual cutting lines L1, L2, and L3 set in the laminated body 27. Thecutting lines L1, L2, and L3 are set in a grid pattern so that channels8 two-dimensionally arranged in the first direction D1 and the seconddirection D2 are carved plural by plural (here, two by two). The cuttingline L1 is set along the first direction D1. The cutting line L1 is setto carve two channels 8 adjacent to each other in the second directionD2 as one set. Each of the cutting lines L2 and L3 are set along thesecond direction D2. The cutting line L2 is set so that the electronincidence portion 8 a of each of the two channels 8 is open at a cutsurface when cutting is performed along the cutting line L2. Further,the cutting line L3 is set so that the multiplier portion 8 b of each ofthe two channels 8 is open at a cut surface when cutting is performedalong the cutting line L3. By cutting the laminated body 27 along thecutting lines L1, L2, and L3 as described above, a plurality of mainbody portions 6 which each include the two channels 8 adjacent in thesecond direction D2 are constituted.

In a subsequent step, the resistive layer and the secondary electronmultiplication layer are formed on the inner surface of the channel 8formed in the main body portion 6 (a layer forming step). Through theabove steps, the electron multiplier body 33 with multiple channels asillustrated in FIG. 11 is manufactured.

In the method of manufacturing the electron multiplier body 33, in thepreparing step, the plurality of first plate-like members 21 areprepared and the third plate-like member 23 is further prepared, and inthe laminating step, the first, second, and third plate-like members 21,22, and 23 are laminated on each other so that the third plate-likemember 23 is interposed between the first plate-like members 21 and thefirst and third plate-like members 21 and 23 are interposed between thepair of second plate-like members 22 to constitute the laminated body27. Therefore, since the first plate-like members 21 are interposedbetween the third plate-like member 23 and the pair of second plate-likemembers 22, a plurality of channels 8 are constituted in the laminatingdirection thereof. Accordingly, it is possible to easily manufacture theelectron multiplier body 33 with multiple channels.

Further, in the method of manufacturing the electron multiplier body 33,a plurality of hole portions 24 are formed in the first plate-likemembers 21 in the hole forming step. Therefore, the plurality ofchannels 8 are constituted in a direction along the surfaces 21 a andthe back surfaces 21 b of the first plate-like members 21. Therefore, itis possible to easily manufacture the electron multiplier body 33 withmultiple channels.

In the above embodiments, the method of manufacturing an electronmultiplier body, the photomultiplier tube, and the photomultiplieraccording to an aspect of the present invention have been described.Accordingly, the method of manufacturing an electron multiplier body, aphotomultiplier tube, and a photomultiplier according to an aspect ofthe present invention are not limited to those described above. Themethod of manufacturing an electron multiplier body, a photomultipliertube, and a photomultiplier according to an aspect of the presentinvention described above may be arbitrarily changed without changingthe gist of each claim.

For example, in the hole forming step, the hole portion 24 may be formedto reach the one end 25 or the other end 26 of the first plate-likemember 21. In this case, before the cutting step, the hole portion 24reaches any one among the one end 25 and the other end 26 of the firstplate-like member 21. Therefore, in the cutting step, the channel 8 canbe open at the one end surface 6 a and the other end surface 6 b of themain body portion 6 by simply cutting only the other of the one end 25and the other end 26 of the first plate-like member 21. Further, beforethe cutting step, the hole portion 24 does not reach the other of theone end 25 and the other end 26 of the first plate-like member 21.Therefore, it is possible to prevent the first plate-like member 21 frombeing divided into two portions. Accordingly, it is possible to improvethe workability. Further, it is possible to make the width of thechannel 8 accurately and conveniently.

Further, as illustrated in FIG. 17, the electron multiplier body 2 maybe a photomultiplier 35 using a photocathode 29 and an anode 30. Thephotocathode 29 exhibits substantially the same shape as a shape of themain body portion 6 of the electron multiplier body 2 when viewed fromthe first direction D1. Further, the photocathode 29 has a flat plateshape. The photocathode 29 is provided on the one end surface 6 a toclose the opening of the electron incidence portion 8 a at one endsurface 6 a of the main body portion 6. Accordingly, photoelectronsgenerated at the photocathode 29 are supplied to the electron incidenceportion 8 a.

The anode 30 receives the secondary electrons emitted from the channel 8according to the photoelectrons incident on the channel 8. The anode 30is provided in the channel 8 to close the opening of the channel 8 atthe other end surface 6 b of the main body portion 6. Accordingly, theanode 30 receives the secondary electrons progressing in the channel 8of the electron multiplier body 2 and reaching the other end surface 6b.

The photomultiplier 35 of this embodiment includes the above-describedelectron multiplier body 2. Therefore, it is possible to suitablyachieve the operations and effects by the electron multiplier body 2.

Further, while the layer forming step is performed subsequent to thecutting step in the embodiments, the layer forming step may be performedsubsequent to the laminating step, or may be performed subsequent to theintegrating step.

Further, the first and second plate-like members 21 and 22 formed of aconductor such as metal may be used. In this case, after the cuttingstep and before the layer forming step, an insulating film forming stepof forming an insulating film on the surface of the main body portion 6and the inner surface of the channel 8 is further performed. In thiscase, since the conductor such as metal can be used as the first andsecond plate-like members 21 and 22, it is possible to manufacture theelectron multiplier body 2 using a variety of materials.

1-13. (canceled) 14: An electron multiplier body comprising: a main bodyportion including one end surface and the other end surface and formedin a rectangular parallelepiped shape extending in a first directionfrom the one end surface; a channel reaching from the one end surface tothe other end surface, opened at the one end surface and the other endsurface, and emitting secondary electrons according to incidentelectrons; a resistive layer and a secondary electron multiplicationlayer formed on an inner surface of the channel; and metal layersprovided on the one end surface and the other end surface, wherein themain body portion is given a potential difference so that the metallayer provided on the other end surface has a higher potential than thatof the metal layer provided on the one end surface, the channel includesan electron incidence portion provided in the main body portion to beopened at the one end surface, the main body portion includes a firstplate-like member that has a hole portion defining the channel and thatis divided into a plurality of parts by the hole portion, and a pair ofsecond plate-like members configuring the channel by closing the holeportion, the first and second plate-like members are formed of aceramic, the main body portion is constituted by laminating the firstand second plate-like members on each other so that the first plate-likemember is interposed between the pair of second plate-like members, andby sintering laminated the first and second plate-like members. 15: Theelectron multiplier body according to claim 14, wherein the electronincidence portion exhibits a tapered shape reduced along the firstdirection. 16: The electron multiplier body according to claim 14,wherein the channel is formed to be bent. 17: A photomultiplier tubecomprising: the electron multiplier body according to claim 14; a tubebody accommodating the electron multiplier body; a photocathode providedin the tube body to face an opening of the channel in the one endsurface, and configured to supply photoelectrons to the channel; and ananode arranged in the tube body to face an opening of the channel in theother end surface, and configured to receive the secondary electronsemitted from the channel according to the photoelectrons incident on thechannel.